Vdu: the Computer Monitoring System

By: Ajibola Daniel

the Visual display Unit (VDU) according to International Labour Office (1989) defined VDU as an electrical instrument that is use to display the information recieved from the computer system,in a very short period of time emerged from comparative obscruity in scientific laboratory(s) to become an integral and indespensable part of normal working life for millions of people both in home and in workplaces. As the technological revolutioncontinues, the use of computer with screen-base output unit or VDU grows at an incresing rate. worlwide, millions of VDUs are now in use, recieving and processing information on television-like screen or monitors. Also, it is a television type monitor that display information recieved from computer system wordprocessor rather than from a signal broad cast for televisio. The VDU contributes the interactive element between the operator and the computer system. The VDU could be limited to a main computer, as with a terminal or the physical entity comporising the VDU could also include the computer system, as with a personal computer (PC). the basic principle of operation of most VDUs in use is simikar to that of television sets.They contain a large evacuated glass tube, called Cathode Ray Tube (CRT), which include a source of electrons (The Cathode) and a phospor coating on thte inside of the vewing face of the screen. A high voltage (typically) in the range of 10-25kv accelerated electrons, releasing from the cathod towards a second electrode called The Cathode. They pass the through a hole in the anode on to the phosphor materials. However, computers are very important and for all the apparent complexity, they seems to hve a wide range of uses and play an ever-increasing role within our society likeoffice, commerce and industries, public services and of course schools and home, with this we can see that the importance of computer monitor can not be over emphasis.

The study is to determine the influence of computer monitor (VDU) a computer system of an organisation and it is stated below:
1.what are the effect of VDU to human and health?
2.what are the control measure and prevention of VDU effect?
3.what are the measuement and level of control of radiation emmision of VDU?

The purpose of this seminar is to provide information on the computer monitor which base on the influence, importance and the uses of computer monitor in a computer system of an organisation.

This project work will be based mainly on the use, importance and the configuration of a computer monitor

During the course of this project work, data were obtained from second sorce, this cisist of information from the periodicals, texetrbooks, encarta software and research findings. Aslo, search engines like www.google.com, www.devilfinder.com, www.mamma.com, and son on will also contacted during the project work.

This research work suppose to go in-depth but due to the power fai.lure, there is no money to move from one place another, insufficient time allocation and the resarch is also expensive to carry out.

In the first generation of computerwhich was between the year 1945-1958 one of the first digital computer in this generation was a machine called ENIAC (Electrical Numerical Integrator and Calculator) was design band built at the Moore school of Electrical Engineering at the univesity of Pennsylvanian in 1956. This ENIAC contained over 18,000 vacuum tubes wieghed more than 30 tons and required 1500 square fact of floor space. It was programmed by setting up to 6,000 switch and connecting cables between the various units of the computer.
The second generation introduced the designing computer which was between (1958-1964) machine based on the store concet using discrete semiconductor element diodes, translator and so on. The vacuum tube was reduce to weighed about 25 tons and required 1000 sqaure of the floor space and again reduction in heat generation. The size-reduction brought by the utilization of semiconductor elements.
Between 1964-1971 which was the third generation f computer which was the third generation of computer which was characterized by further reduction in sixe of the VDu low cast, low in heat generatiion. Introduction of im[proved method of storing datas and applicaron of Integrated Circuits (I.C.), they accepted their input data through magnetic tape and magnetic disk, which they also accepted for secondary storage.
During 1971-1975, Here computer were first designed on the basis of large-scale integrated circuit along with vacuum 3tube and transistror. Each electronic along has its own set of characteristics including reliability, packing density, heated dissipation, speed and cost of all which designer must balance then the VDU size was drastically reduced compare to the first generation and the cost which is very cheap. This fourth of computer are otherwise known as microprocessor on a chip and is characterized by the energence of personal computer (PCs) so called foruth generation programming language such as spread sheet, Dbase III, windowing menu dialoging and other paraphernalia.
The fifth generation of computer (1975-1995) is the mother language or lingual franca of each user. Hence the following thechonolgies were involved in the fifth generation; (1) Micro electronics (2) computer architecture (3) Artificial intelligence (4) Language processing (5) database management. A logical influence is an elementary inductive method of reasoning and each lips is equivalent to some 300 instruction on a conventional computer.
The sixth generation of computer monitor was the geneation which innovation called Optic Computer, the computer of this generation is from year 1995 till date and the computer of this generation are laptop computer, palmtop computer, plasma computer all which are usin a flat screen are been constructed. Here are the computer monitor that came into being in this generation MDA (Monocrono Display Adapter), HA (Hercules Adapter). CGA (Color Graphic Adapter), LCD (Liquid Crystal Display), Palmtop Plasma Television and so on.

The Monitor could be linke to a main computer, as with a terminal, or the physical entity comprising the VDU could also include the computer system, as with a personal computer (PC). The basic principle of operation of most VDUs in use is similar to that of television sets. They contain a large evacuated glass tube called Cathod Ray Tube (CRT), which include a source of electrons (the cathode) and a phosphor coating on the inside of the viewing face of the screen. A high voltage (typically in the range of 10-25kv) accelerates electrons release trom the cathod towards a second elctrode on to the direction and thus the impact of the points of the electrons on the phosphor are controlledby magnetic field produced by deflecting the coils mounted near the back of the tube. In this manner, the electron beam is swept horizontally and vertically across the viewing face-the whole face normally being-covered in about 1/70th of a second. By modulating the intensity of the electron beam in each position, the resulting pattern of light and dark points can be generated into pictrue. The electronic circuit used to control these processess gives rise to both radio frequency (RF) field and to electric and magnetic fields of lower frequencies. Recently, solid state circuitry in conjuction with liquid crystal, gas plasma or similar display technology(s) has been used to replace cathode ray tube. However, to a rather limited extent.

Computer:- an electronic device capable of storing and processing information in accordance with a set of instruction.
Cathode Ray Tube:- a vacuum tube in which beam of electrones produce a luminous image on a fluorescence screen, used in television and display unit (VDU).
Monitor:- a television used to view a pictrue from a particular camera o a display from a computer.
Monochrome:- consisting of or display image in black and white or in varying tones of one color.
Hercules:- requiring or having greate strnght or effects.
Flash:- shine with a bright but brief or irregular light.
Pixel (Pictrue Element):- any of the tiny ray of light on a display screen which are made up of an image.
Pallete:- a thin board on which an artist lay anf mixes pints abd the range of color used by an artists.

In conclusion, there are no health hazards associated wityh radiation, graphic adapter and field from VDUs. However, since a large number of people are involved in VDU work measure sohould be taken to ensure that VDU workplace are economically well designed. This include aspect of the VDU, the workstation and the work environment as well as work organiszation.

Bergqiust, U. (1984), "Video Display Terminals and Health", in scandinavia via journal of work environment and
health (helsinkin), vol.10.
Health and Welfare (Canada).1993), Investigations of Radiation Emission from Vidoe Display Terminals, Reporter 83-
-91 (Ottawa, Environment Health Directorate).
Intenational Labour Office (ILO), 1989. Working With Visual Display Unit, Occupational safety and Health Series
No. 61.
Locksley E.A. et al (2006). Introduction to Computer Studies 1, Immacuilate Concept, Ogbomosho, Oyo state
Pg. 3-7.
Micheal Tooley (1997), PC Troubleshooting Pocket Book, the bath press Pg. 150.


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